Telephone-key.



J. L. MOQUARRIE.

TELEPHONE KEY.

APPLICATION FILED NOV. 23, 1907.

Patented Aug. 17, 1909.

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"UNITED srnrns rnrnn r est" JAMES L. MCQUARRIE, OF OAK PARK, ILLINOIS, ASSIGNOR TO WESTERN ELECTRIC COMPANY, OF CHICAGO, ILLINOIS, A CORPORATION OF ILLINOIS.

TE LE PHONE -KEY.

Application filed November 23, 1907.

To all whom it may concern:

Be it known that I, JAMES L. MoQUAnnrn, citizen of the United States, residing at Oak Park, in the county of Cook and State of Illinois, have invented a certain new and useful Improvement in Telephone Keys, of which the following is a full, clear, concise, and exact description.

My invention relates to telephone key construction, and its object is to provide a simplified arrangement of keys and associated contacts in which each key in addition to controlling the operation of contacts individual thereto, is adapted to operate contact or contacts common to all of said keys.

In my co-pending applications, Serial No. 403,510 filed November 23, 1907, and Serial No. 403,511 filed November 23, 1907, I have shown circuit arrangements and key constructions for an intercommunieating system in which a plurality of local'keys are adapted to release each other, and the last-operated key to remain locked in its operated position, there being a common ringing key, operating independently of said other keys, to apply ringing current to the circuit closed by the operated local key. Such an arrangement provides a distinct ringing key, and for the party at one local station to call u another station it is necessary that a loca key be first depressed and that the ringing key be subsequently depressed. By my present invention, the ringing key is omitted and an arrangement is provided by which the ringing contacts may be closed by the operation of any one of said local keys.

My invention consists of a group of keys each having a contact or contacts individual thereto adapted to be operated by the corresponding key, combined with a contact or contacts common to all of said keys and adapted to be operated by any one of said keys.

More specifically, my invention comprises a plurality of plunger keys each adapted when depressed to be locked in position to close the contacts individual to such key and each adapted when further depressed to close a pair of contacts common to all of said keys, said operated key automatically returning to its first locked position when the pressure is removed therefrom.

My invention may be more readily under- Specification of Letters Eatent.

Patented Aug. 17, 1909.

Serial No. 403,512.

stood by reference to the accompanying drawings, in which- Figure 1 is a side elevation of a device enibodying my invention, parts being broken away to more clearly show the structure thereof, and the keys being shown in their normal unoperated positions; Fig. 2 is a fragmentary detail view showing one of said keys in its first or locked position; Fig. 3 is view similar to Fig. 2, but showing the position of the parts upon a further depression of the key; Eig. ais an end elevation of the device.

Similar letters of reference designate the same parts wherever shown.

The face plate 1, and the base plate are mounted on a frame A and have the plunger rods 3 of the keys L mounted therein. in the usual manner. Each plunger rod is provided with the usual conical plunger 1- con.- trolling the opening or closing of the associated contacts 5, G.

Mounted in the frame A is the usual spring-retracted movable plate 7, having openings 8 of a size to permit the passage of conical plunger 9 on each plunger rod 3. The plunger is adapted to engage beneath the plate 7 and hold the key depressed, as shown in Fig. 2. If a key L in the unoperated position shown in Fig. i be depressed, the conical plunger 9 will engage with the sides of the opening 8 and move the plate '7 against the tension of its retractile spring, thereby releasing any key that may be depressed. Upon the plunger 9 passing through the opening 8, the plate will be retracted to its normal position, locking down the plunger 9. When the plunger rod 3 is depressed sufiiciently to be locked down in the manner just described, contacts 5 and 6 are closed by the plunger 4.

Mounted in the frame A beneath the plate 7 and suitably spaced therefrom is a second movable plate 10 provided with enlarged openings similar to the openings 8 in plate 7. The plate 10 is held in the normal position shown in Figs. 1 and 2 by a spring 11, which bears against a downturned flange 12 on said plate.

Nhen the key L is depressed beyond the position shown in Fig. 2, the conical plunger 9 moves the plate 10 and with it the spring 11, thereby closing the contact 13 while the plunger 4 maintains contacts 5 and 6 closed. As shown most clearly in Fig. 3, even when the key is depressed to its utmost limit, the plunger 9 is not depressed sufficiently to pass beneath the plate 10, and hence when pressure is removed from the key L it is restored by the spring 14 to the position shown in Fig. 2, whereupon the plate 10 is returned to its initial position by the spring 11.

It will be observed that the plate 10 is adapted to be moved in the above-described manner by any one of the keys L.

Assuming that the above-described key structure is used in connection with an interconnnunicating system, as for example with the. system shown in my above-mentioned co-pending applications, it will be noted that a plurality of local keys are each provided with a listening position as shown in Fig. 2-; that upon the further depression of the key to a ringing position, shown in Fig. 3, ringing current may be applied to the local circuit closed by the key; and that upon removing the pressure upon the key, said key is automatically restored to its listening position.

While in the dr wings I have shown two movable plates each adapted to be operated by a single conical plunger at different positions of depression, obviously my invention is not necessarily limited to such details of construction.

I claim 1. In a switching device for an intercommunicating telephone system, the combination with a plurality of keys each having a i'iormal unoperated position, an operated listening position and an operated ringing position, contacts individual to each key arranged to be closed by the key in the said operated positions, a contact or contacts common to said keys, and a common means operable by each of said keys for closing said common contact when the key is in its ringing position.

2. In a switching device for an intercommunieating telephone system, the combination with a plurality of spring-retracted plunger rods, each having a normal unoperated position, an operated listening position and an operated ringing position, a plunger associated with each plunger rod, contacts individual to each plunger and arranged to be closed thereby in the operated positions of the plunger rod, a spring-retracted locking plate common to said rods for holding a plunger rod locked down when depressed to its listening position, a contact common to said plunger rods, and a movable plate operable by each of said rods in its ringing position for closing said common contact, said movable plate permitting the retraction of the plunger rod to its listening position when the downward pressure is removed from the plunger rod.

3. The combination with a plurality of spring retracted plun er rods, each provided with a contact operating plunger, of contacts individual to each plunger and arranged to be operated thereby, a plate cooperating with said plungers for locking said plunger rods, a contact common to said plunger rods, and a second plate movable by said plungers to control said common contact.

4. The combination with a plurality of spring-retracted plunger rods each provided with a contact operating plunger, contacts individual to each plunger and arranged to be operated thereby, a movable upper plate, a plate operating plunger on each of said rods adapted to engage beneath said movable plate to maintain. said contact operating plunger in its depressed position, a lower movable plate beneath said upper plate and spaced apart therefrom, said lower plate being arranged to be moved by said plate op erating plunger without having locking engagement therewith, and a common contact controlled by said lower plate.

In witness whereof, I hereunto subscribe my name this ninth day of November A. D.

JAMES L. liloQUARRIE. Witnesses:

-WILLIAM MoA. SMITH, EDWARD B. CRAFT. 

